This disclosure relates generally to light emitting diodes (LED) dice and more particularly to light emitting diode (LED) dice having wavelength conversion layer and to methods for fabricating light emitting diode (LED) dice with the wavelength conversion layers.
Light emitting diode (LED) dice have been developed that produce white light. In order to produce white light, a blue (LED) die can be used in combination with a wavelength conversion layer, such as a phosphor layer formed on the surface of the die. The electromagnetic radiation emitted by the blue (LED) die excites the atoms of the wavelength conversion layer, which converts some of the electromagnetic radiation in the blue wavelength spectral region to the yellow wavelength spectral region. The ratio of the blue to the yellow can be manipulated by the composition and geometry of the wavelength conversion layer, such that the output of the light emitting diode (LED) die appears to be white light.
In this type of light emitting diode (LED) die, the characteristics of the white light are determined by the electromagnetic radiation emitted by the blue LED die and by the wavelength conversion properties of the wavelength conversion layer. For example, the color composite of the white light depends upon the spectral distributions of electromagnetic radiation produced by the blue LED die and the wavelength conversion layer. Any variations in these spectral distributions can vary the color composite of the white light produced by the light emitting diode (LED) device. Because of the variations in the configurations of the blue LED die and the wavelength conversion layer, the white light can have an undesirable color balance and lack the characteristics of a true color rendition.
It is difficult to fabricate white light emitting diode (LED) dice with consistent color balance because any variations in the fabrication process can change the outputs of the light emitting diode (LED) dice and the wavelength conversion layers. The present disclosure is directed to a method for fabricating light emitting diode (LED) dice with wavelength conversion layers.